Eddy current sensors can be used, as is known for example from DE 196 31 438 A1, which is incorporated by reference, to determine the distance between a measuring body and a coil.
Inductive angle sensors that use eddy current sensors are known by way of example from DE 10 2004 033 083 A1, which is incorporated by reference. The eddy current sensor comprises a coil for generating eddy currents in a conductive measuring body and the measuring body itself. The coil and the measuring body can move relative to one another in a movement direction. The measuring body comprises a conductive track that is designed in such a manner that the inductance of the coil changes continuously, that is to say periodically, as the track is scanned in the movement direction. It is possible in this manner to perform time-continuous incremental angle measurements.
Moreover, it is known from DE 10 2009 033 242 A1, which is incorporated by reference, to ascertain an angle of rotation index using eddy current sensors.